In railroad track installations, the steel railroad rails are generally fastened with steel railroad spikes to supporting creosote-saturated wooden cross-ties, the latter of which are laid in parallel fashion at right angles to the steel rails on a roadbed consisting of packed rock aggregate in the following manner:
A steel plate of the same width as the horizontal width of the wooden cross-tie, and generally twice as long horizontally as the width of the steel railroad rail bottom flange, is centered between the steel railroad rail bottom flange and the underlying wooden cross-tie. This steel plate has a number of square holes in the exposed portion on either side of the portion underneath the steel railroad rail bottom flange. Each hole is large enough to allow entry of a steel railroad spike to pass through. The holes are spaced to allow the bottom flange of the railroad rail to fit between them, and are close enough to the edge of the railroad rail flange to permit the head of the steel railroad spike to engage the rail flange when the spikes are driven through the holes in the steel plate into the underlying wooden cross-tie, thus anchoring the railroad rail to the wooden cross-tie. Wooden cross-ties split when the railroad spikes are driven into them, causing them to loosen.
Wooden cross-ties are flexible, and deflect downwards under the vertical load imposed through the railroad rails by a passing train at the area just under the steel support plates, but not under the portion of the wooden cross-tie that lies between the two parallel railroad rails. Prolonged loosening of the railroad spikes eventually allow the railroad rails to move apart, with danger of train derailment.
The high localized load imposed by a passing train on the railroad rails causes deflection of the cross-tie at the area directly under the steel plate, pushing the underlying packed rock aggregate downwards, and loosening the steel railroad spikes in the wooden cross-tie. Attempts to maintain an evenly packed aggregate roadbed are costly, requiring repeated tamping of the aggregate to restore the roadbed directly underneath the railroad rail cross-tie at the steel plate area.
Wooden railroad rail cross-ties also dry out over periods of time, which further aggravates the splitting of the wood in the area of the driven railroad spike. The present procedure for overcoming the drying-out of the wooden cross-ties includes re-creosoting of the wooden cross-ties by spraying creosote directly on the entire roadbed. This pollutes the ground, and eventually this known carcinogen, creosote, leaches into the underlying groundwater aquifers. Over time, the creosote contamination of groundwater aquifers can pose an environmental threat to human health.
The cost of re-ballasting roadbeds, and re-driving or replacing loose steel railroad spikes, creosoting entire railroad roadbeds for in situ treatment of wooden railroad cross-ties and eventual replacement of the wooden crossties, is one of the major maintenance costs of the nation's railroad corporations. The hazard of loosened railroad spikes constitute the primary reason for derailments of railroad trains.
Prior art shows that inventors as far back as Wolfe, U.S. Pat. No. 790,670 in 1905 and Wessels, U.S. Pat. No. 972,303 in 1910 recognized this problem and attempted alleviation with the use of concrete railroad crossties. Immediate problems occurred with anchoring the steel railroad rails to the concrete, as evidenced by a number of following patents, such as Maas, U.S. Pat. No. 1,069,447, Yeomans, U.S. Pat. No. 1,795,817 and Waltz, in U.S. Pat. No. 2,250,785. Problems of high initial installation cost, security, high ongoing maintenance, and aquifer contamination remain despite past prior art efforts.
Attempts to prolong the life of existing wooden crossties by the installation of covers have been addressed by Harmsen, U.S. Pat. No. 4,609,144 in 1986 and attempts to minimize yielding or shifting of roadbed aggregate by filling empty rubber tires with loose aggregate have been addressed by Frohn, U.S. Pat. No. 5,172,858 in 1992.
The present invention addresses the above-mentioned prior art by eliminating wooden crossties, which are a major source of forest depletion; eliminating creosote thus preventing further degradation of drinking water aquifers from this source of pollution; providing a railroad rail support member with a contained railroad spike receptor that prevents railroad spike withdrawal or loosening without any tightening or locking devices; and eliminating any slippage between railroad rail and railroad rail support member by eliminating the use of separate steel support plates previously used for an interface between the railroad rail and the wooden crosstie.
A further advantage of the present invention is the simplification of fastening the railroad rail to the underlying railroad rail support member by virtue of a driven railroad spike into tubular channels which have a bend in them, thus bending the railroad spike when it is driven and thus preventing any upward loosening of the railroad spike when continual vertical compressions and tensions take place by the multiplicity of passing train wheels. The invention touches on the present art of having the bent portion of the railroad spike at least 30.degree. of incline from the vertical plane of the downwardly projecting railroad spike into the tubular channel of the railroad rail support means. Lesser angles of incline tend to allow the railroad spike to withdraw under upward deflection of the railroad rail between compressive loading impacts of the passing train wheels.
This differs significantly from Harmsen, U.S. Pat. No. 3,039,695 and Vivion, U.S. Pat. No. 4,216,904 in that threaded studs are utilized for tightening and holding the totality of their constructions tightly to the railroad rails. The present invention simplifies significantly the total procedure, allowing the railroads companies to utilize the present steel railroad spike, together with conventional spike driving means presently used for driving steel railroad spikes into wooden crossties. No tightening of nuts or re-tightening of same is necessary, as all nuts and bolts are eliminated from the construction.
Other improvements in simplification are achieved by this invention through elimination of such means as Waltz, U.S. Pat. No. 2,250,785 which incorporates the adjustable downward force-locking effect of the weight of the railroad rail to hold the rail tight to the cross-tie, which can loosen and allow railroad rail displacement with the compaction of underlying aggregate by recurring compressive loadings by passing train wheels which can allow individual crossties to slump continually lower to the point where the weight of the railroad rail itself is no longer bearing on the locking construction, thus allowing it to open.
The attempts to prolong the life of existing wooden crossties by the installation of elastomeric covers that have been addressed by Harmsen, U.S. Pat. No. 4,609,144 in 1986 and the attempts to minimize yielding or shifting of roadbed aggregate by filling empty rubber tires with loose aggregate that have been addressed by Frohn, U.S. Pat. No. 5,172,858 in 1992 are applicable to wooden cross-ties, which this invention eliminates in the first instance; and by the incorporation of rubber tires as an integral support member designed to yield maximum load distribution over the roadbed aggregate, thus minimizing the tendency to shift that a "floating" rubber tire, not being an integral part of the railroad cross-tie member would have in the second instance.